Fuel injection system



Feb. 16, 1932. 1-1.1; HERR 1,845,600

FUEL mmc'i'xou SYSTEM Filed July 12, 1928 s Sheets-Sheet 1 vwfrmiss vINVENTOR (5 l H-T-Hc'rr BY 05 W ATTORNEY Feb. 16, 1932.

FUEL INJECTION SYSTEM 3 Sheets-heet Filed July 12, 1928 Fig.4;

'INVENTOR FLT-Herr ATTORNEY Feb. 16, 1932. H. T. HERR 1,845,600

v FUEL INJECTION SYSTEM Filed July 12, 1928 s Sheets-Sheet s I a l A 5WITNESS liNyIETiOR I I Gr! 61% I BY ATTORNEY Patented Feb. 16, 1932UNITED STATES.

PATENT FFIQE HERBERT T. HERB, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TOWESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OFPENNSYLVANIA FUEL INJECTION SYSTEM Application filed July 12,

My invention relates to pumps and especially to liquid fuel pumps forinternal combustion engines, and has for its object the provision ofapparatus of the character des- 5 ignated which shall be simple ofdesign, easy of manufacture, and efficient in operation.

A further object of my invention is to pro vide a pump which shall beeffective to deliver a metered quantity of'fluid at a req- 1o uisitepressure and which pump shall include means for readily varying thequantity of the fluid delivered and, if desired, the time of delivery.

A still further object of my invention is to provide a liquid fuel pumpfor an internal combustion engine which shall be effective to deliver ametered quantity of liquid fuel to the engine cylinder at injectionpressure and which shall include means for readily varying the quantityof fluid so delivered as well as the time of delivery.

A still further object of my invention is to provide, with amulti-cylinder internal combustion engine, a plurality of fuel pumps forsupplying the cylinders and which shall include means for varying thefuel pumped by all of the pumps in unison and individual .adjustn'icntof each of the pumps with respect to the other.

Liquid fuel pumps, as heretofore known to me, have been very difficultto design due to extremely high pressures required to be developed, theminute quantities of liquid fuel required to be injected into a cylinderfor each power stroke thereof, requiring accurate metering, and theleakage through the valves or parts of the pump which necessarilyreacted upon the pressure and metering of the liquid fuel.

In accordance with my invention, I have overcome the beforementioneddifficulties and have provided a pump far simpler inconstruction andoperation than any heretofore known to me, and which embodies meanswhereby leakage is reduced to a minimum and wherein wear on the valvemeans included in the pump tends rather to reduce leakage than toincrease it. Briefly, my invention comprises a housing defining acylinder having inlet'means terminating in a 1928. Serial No. 292,197.

port in the wall of the cylinder and outlet means at one end thereof, aplunger reciprocating in the cylinder, and valve means carried by theplunger and effective-to open and close the inlet to the cylinder. Thevalve means are preferably so arranged with respect to the plunger that,when the inlet port is closed during the pressure stroke of theplunger,the plunger is at its most rapid rate of reciprocation, althoughit is possible to vary the speed of opening and closing the inlet portat will, the pump being capable of adjustment so as to effect relativelyquick closing and slow opening, or quick closing and quick opening, orslow closing and quick opening, etc. The result of this is' to entraptheliquid fuel ahead of the plunger and strike it a hammer blow,instantly developing a very high pressure ahead of the plunger andforcing it through a suitable injection device into the engine cylinder.The beforementioned valve means is provided with a face of varyingeffective closing area and there is included means for operating thevalve so as to effect a varying duration of the injection period.

Where a number of my improved pump units are associated with amulti-cylinder internal combustion engine, means are provided foroperating all of the valve means in unison and also for adjusting anyone of the valves with respect to the others. The valves are operated tovary the injection period of the pump, preferably in accordance with theload on the engine. In addition, I provide means for timing thebeginning of the pressure stroke of the plunger and preferably do thisin accordance with the speed of the engine.

Apparatus embodying features of my invention is illustrated in theaccompanying drawings, forming a part of this specifica tion, wherein:

Fig. 1 is a view in elevation of my improved pump as associated with aninternal combustion engine cylinder;

2 is a View in elevation, showing a plurality of my improved pumpsassociated with a mult-i-cylinder internal combustion engine;

Fig. 3 is a longitudinal vertical section of my improved pump;

Fig. 4 is a detailed View of a part of the pump controlling means;

Fi 5 is a sectional view taken along theline V of Fig. 4;

Fi. 6 is a sectional view taken along the line I-VI of Fig. 3;

Fig. 7 is a sectional view taken on the line VII-VII of Fig. 3;

Figs. 8 and 9 are enlarged, partial views of the plunger valve and pumpcylinder shown in Fig. 3, Fig. 8 showing the angular position of theplunger valve relative to the cylinder for a relatively long and lateperiod of fuel injection, and Fig. 9 showing the angular position of theplunger valve relative to the cylinder for a relatively short and earlyperiod of fuel injection;

Fig. 10 is a partial view of another embodiment of my invention andshows a form of plunger valve and cylinder which is similar to F1gs.'3,8 and 9, except that it is so arranged that the timing of the fuel1!1]GCt-1011 period is constant irrespective of its duration;

Fig. 11 is a partial view of still another embodiment of my inventionand shows a form of plunger valve and cylinder which is similar to Figs.3, 8 and 9 except that it is arranged to provide relatively earlyinjection of fuel for long periods and relatively late injection of fuelfor short periods;

' Fig. 12 is a partial view, in sectional elevation, of anotherembodiment of the fuel valve shown in Figs. 3 and 7 in which embodimentthe valve entirely surrounds the pump plunger and wherein a separatepassageway is provided for transferring fuel between the oppositelydisposed lateral faces of the valve; and

Fig. 13 is a plan view, in section, taken on the line XIII-XIII of Fig.12.

Referring now to the drawings for a better understanding of myinvention, I show in Fig. 1, at 10, a fragment of an internal combustionengine cylinder provided with a fuel injection device 11. At 12, isshown my 1mproved pump for supplying liquid fuel under pressure to thecylinder through the in] ection device 11. The pump comprises a housing13 defining a cylinder 17 (Fig. 3), said cyllnder having a liquid fuelinlet port 14 which communicates with a suitable liquid fuel supplyconduit 16, which latter may be connected to any suitable source ofsupply. WVhile I have termed the port 14 an inlet port, neverthelessthis port is also utilized to discharge fuel from the cylinder asdescribed hereinafter. The liquid fuel supplied through the conduit 16should be, preferably, at a suflicient initial pressure to pass freelyinto the pump. For example, in Fig. 1, I show a gear pump 15 pumpingfuel from a reservoir into the conduit 16 which may include anaccumulator in the line for insuring an even pressure in the conduit.Overflow from the accumulator 30 may return to the fuel reservoirthrough a conduit 31' as shown. Referring again to Fig. 3, a.reciprocable plunger 18 operates within the cylinder 17 developingliquid fuel under pressure which is discharged from the cylinder throughan outlet 19 in the upper end of the cylinder and thence through aconduit 21 to the injection device 11.

Carried by the plunger 18, is a valve 22 formed integrally with theplunger 18. As shown in Fig. 7, the valve 22 may not extend entirelyaround the plunger 18 so that on one side of the valve a longitudinalopening 23 is provided which permits fluid to freely pass from one sideor lateral face of the valve to the other side or lateral face of thevalve and permits liquid fuel under pressure within the cylinder 17 toact against one side of the valve and exert an unbalanced effect thereonwhen the inlet port 1-1 is closed, forcing the valve tightly against theport 14. While, in Fig. 7, the valve does not extend entirely around theplunger, nevertheless, it is obvious that I may arrange the valve sothat it does entirely surround the plunger, as shown in Figs. 12 and 13.In the latter figures a separate passageway 23' extends longitudinal yand radially through the plunger and permits the fuel to transfer fromone lateral face of the valve to the other. The valve 22 reciprocates infront of the inlet port 14, so that at each stroke of the plunger 18 thevalve opens and closes the inlet port 14. x

In the drawings, Fig. 3, the plunger 18 is at the mid stroke with theinlet port 14 closed. Assuming that the plunger 13 is at its outerposition, the cylinder 17 will be filled with liquid fuel. During thefirst portion of the inward or working stroke of the plunger 18 anduntil the valve 22 covers the suppl port 14, liquid fuel will beexpelled bacli through the supply port 14; when the valve 22 covers thesupply port 14, liquid fuel will be entrapped in the cylinder 17 and theplunger 18 will impart a hammer-like blow to the fuel causing very rapiddevelopment of pressure and consequent injection of fuel through theinjection device; and during the final stage of movement of the plunger18 during the working stroke, when the valve 22 uncovers the supply port14, the builtup injection pressure is suddenly relieved, there bypermitting of. instant cessation of fuel injection. During the outwardstroke of the plunger 18, the cylinder 17 fills with liquid fuel, firstfrom the supply port until the latter is covered by the valve 22 andthereafter from the time the supply port 14 is uncovered by the valve 22and until the end of the outward or suction stroke. As will be moreclearly seen hereafter, closure of the supply port 14 by the valve 22preferably takes place during the most rapid speed of reciprocation ofthe plunger 18.

The fuel thus entrapped is acted upon by the plunger 18 in amannerstriking it a hammer blow and developing a. pressure requisite forinjection purposes, discharging the liquid fuel outwardly through theoutlet 19. As soon as the valve 22 has passed over the inlet port 14 onits outward stroke, liquid fuel in the cylinder 17 passes from the uppertransverse or lateral face of the valve to the lower transverse orlateral face of the valve through suitable passageway means, such as theopening 23, and outwardly of the cylinder through the inlet port 14until the plunger has completed its upward stroke.

It will be seen from the foregoing that the duration of the injectionperiod into the engine cylinder is determined by the duration of theclosure of the inlet port 14 while the plunger 18 is moving inwardly. Inorder that this period may be varied, and in order that the time ofinjection may be varied, I dispose the leading and trailing edges ormargins of the valve angularly with respect to the direction ofreciprocation so as to form in effect asomewhat triangular-shapedhearing surface for the valve against the walls .of the cylinder. Whenrelative rotation between the valve 22 and the cylinder 17 occurs, alonger or shorter face portion of the valve is caused to be opposite theinlet port 14, and, in addition, the leading edge or margin of the valveregisters earlier or later with the fuel inlet port. The method ofaccomplishing this result will now be described.

The plunger 18 is driven from a shaft 26 through an eccentric 27, aconnecting rod '28 and a cross-head 29. The plunger 18 is connected tothe cross-head 29 in a manner to be presently described. The cross-head29 is connected to the rod 28 through a ball and socket joint 31,whereby the cross-head 29 is freely rotatable with respect to theconnecting rod 28.- The cross-head 29 is cylindrical in cross-sectionand reciprocates within cvlindrically-shaped guide means 32 so that itis freely rotatable with respect to the guide means. The cross-head 29is provided on its outer periphery wit-h longitudinally-extending teeth33. Carried by the guide means 32 is a rack 34 having teeth 36 providedthereon and meshing with the teeth 33.

The rack 34 maybe operated by any suitable means, either automaticallyor manually, in order to vary the relative position of the valve 22 withrespect to the inlet 14 and thus vary the quantity of fuel being fed tothe engine. For example, in Figs. 1 and 2, I show a. lever 37 carrying,a latch 38 which fits in a. quadrant 39 and which is connected to therack 34 through a link 41. By this means the operator may vary theamount of fuel being pumped in accordance with the load on the engine.

lVhere a plurality of pumps are employed in connection with amulti-eylinder internal combustion engine it is desirable that all ofthe pumps be operated in unison so that each of the cylinders mayreceive its pro portionate. supply of fuel. I, accordingly, form therack 34 with teeth 42 at right angles to the teeth 36 and which meshwith a pinion 4-3. The pinion 43, Fig. 2, is made to extend along all ofthe pumps so as to mesh with all of the racks 34, whereby, when one ofthe racks 34 is moved back and forth, it. causes similar movement of allthe other racks through the pinion 43. While, in Fig. 2, I have shown aseparate fuel pump for each cylinder, nevertheless it is to beunderstood that I may utilize a single pump to supply fuel to aplurality of cylinders. In addition, my fuel pump is adapted to supplyfuel to either a single or a plurality of cylinders, whether the enginesbe of the two-cycle type or four-cycle type, the speed of the pump driveshaft 26 being made to suit the conditions.

In addition. I prefer to so dispose the racks that they will not haveimposed upon them the side thrust of the plunger cross-head and one wayof accomplishing this, as will be noted from Figs. 1, 2 and 3. is tohave the eccentric 27 and the racks 34 lie in planes parallel to eachother. The reason the rack 34 is thus disposed is to place it inposition where it will not have imposed upon it the side thrusts of thecross-head 29 due to the action of the eccentric 27. With the pumpsdisposed as shown in Fig. 2 this locates all of the racks 34 inparallelism, and with the pinions 43 extending at right angles to theracks. In this manner none of the racks is subiected to the side thrustsof their associated crossheads.

In an installation, such as is shown in Fig. 2, it may happen that oneof the pumps shown would deliver a different amount of fuel to itsassociated cylinder than the remaining pumps and it would therefore bedesirable that such a pump be adjustable' so as to bring it in unison ofoperation with the other pumps. I accordingly form, as shown 1n Figs. 4and 5, each of the racks 34 in two parts and join the parts together bymeans of a bolt 46 which screws through one of the parts and into theother. The bolt 46 is provided at one end thereof, in the example shown.the left-hand end, with right-handed threads 47 fitting into similarlyformed threads in the left-hand part, as shown. The

of the rack meshes with the pinion 43, the pinion 43 acts as anabutment. causing that part of the rack meshing with the cross-head 29to move with respect thereto and thus imparts an angular movementto thevalve 22 and varies the period of injection of that particular pump.After the desired adjustment is made. the bolt 16 is locked in positionby means of a lock nut 49. It will be seen that this adjustment can bereadily made while the engine is running. As shown in Fig. 3, acompression spring 50 is preferably interposed between each adjustablerack 3-1 and the pump housing 13 to take up the back-lash of the rack onthe cross-head 29 and the pinion 43.

A further refinement in the design of my improved pump lies in the meansprovided for joining together the plunger 18 and the cross-head 29. Theplunger 18, Fig. 6, is formed with a squared head 51 fitting within arecess oilformcd in a washer 5; The washer is provided with parallelsides and fits in a complementary recess 54 formed in the cross-head. Aslight movement is permitted in one direction between the cross-head 2E)and the washer 53, while a slight movement atright angles to themovement just described is permitted between the plunger head 51 and the'ashcr 53. The whole is held together by means of a nut 56 screwing intoa suitably formed recess in the cross-head 29 and bearing down upon thewasher and the plunger head. By thus fitting the cross-head and theplunger together, the machining of the cylindrical guides 32 withrespectto the :ylinder 17 is simplified in that it is not absolutelynecessary that they be machined with coinciding centers. The slightmovement permitted between the cross-head and the plunger permits thecross-head to turn without imposing a side stress upon the plunger,which might entail undue wearing of the cylinder, it being understood,of course, that the plunger 18 must be as nearly fluid-tight withrespect to the cylinder 17 as is possible.

The pump shaft. 26 is driven from the engine shaft 55 having a pinion 56thereon meshing with the gear 57 connected to the shaft 26. The phaserelation of the pump or pumps with respect to the engine may be variedby varying the angular relationshi of the gear 57 with respect to thepump shaft 26; and, to this end, I provide a longitudinally movablesleeve 58 having a steep threaded connection with respect to a shaftextension 59 on the gear 57 and connected by a spline 61 to the shaft26. The sleeve 58 may be shifted longitudinally in any suitablemanneiyas, for

example, by the lever (33.

The operation of the apparatus so far de scribed will now be explained.As the shaft 26 rotates, .itcauses the plunger 18 to reciprocate withinthe cylinder 17 carrying with it the valve 22, to and fro across theinlet port 14. Liquid fuel under sufficient pressure to cause it toenter the cylinder 17 is supplied through the conduit. 16 and enters thecylinder 17 during the inward stroke of the plunger. llpon an outwardstroke of the plunger 18. when inlet port 11 is not covered by valve2:2. liquid fuel is forced outwardly of the pump through the inlet port14. This continues until the upper edge or margin of the valve 22 cutsoff the port 11 whereupon the liquid fuel above the plunger is entrappedin the cylinder 17 and a pressure sutliciently high for injectionpurposes is immediately produced. As will be seen from consideration ofFig. 3, the arrangement may be such that this occurs during the mostrapid speed of reciprocation of the plunger 18 so that the entrapped oilabove the plunger is, in effect. given a hammer blow by the plungerwhich ctt'ects an immediate production of an extremely high pressure.The pressure produced within the cylinder 17 acts on the valve to pressit tigl'itly against the wall of the cylinder over the port 14 so thatno leakage can occur outwardly through said port. This feature of theinvention is extremely important as the tendency to leakage in fuelinjection pumps has heretofore been one of the major dillicultics to beovercome. After the lower edge or margin of the valve ,22 has passedover the port 14;. fluid is by-passed through the Irv-pass groove 2; andoutwardly of the inlet port 1-} until the plunger has completed itsoutward stroke.

The amount of fuel to be injected at each stroke of the plunger varieswith the load and may be regulated in any suitable manner as by thelever 37 through the racks 34 and the cro. shead 2t). \Vherc a pluralityof pumps are employed. the racks associated.

with the respective pumps are all operated in unison through the pinion43 which meshes with all of the racks. Where an individual pump requiresadjustment relative to the other pumps, this can be accomplished byturning the adjusting screw 48 which alters the relative position of theracks 36 and 42 and consequently changes the angular position of theplunger 18.

Referring now to the detail operation of the valve 22. reference may behad to Figs. 8 and 9 wherein an enlarged view of the inlet port 14 isshown. As is apparent from these figures. the inlet port 14 ispreferably made somewhat triangular in shape, its upper edge 64: and itslower edge 65 being disposed substantially parallel with the leading andtrailing edges or margins, respectively, of the valve 22. Such a form offuel inlet port is especially adapted for engines of the highspeed typewherein the time available for filliug the cylinder 17 of the pumpduring the suction stroke is so shortthat difficulties are sometimesencountered in securing the proper amount of liquid fuel in the cylinderbefore While I have shown myinventionin several forms, it will beobvious to those skilled in the art that it is not so limited, but issusceptible of various other changes and modi iications withoutdeparting from the spirit thereof, and I desire, therefore, that, onlysuch limitations shall be placed thereupon as, are imposed by the priorart or as arespecifically set forth in the appended claims.

What I claim is: a

1. In a fuel pump for a high speed internal combustion en ine, thecombination ofa ump cylinder avingahead portion, fuel inlet and fueldischarge assages provided in the cylinder, said fuel ischarge passagebe1 ing located near the head portion andsaid fuel inlet passage beingspaced from the discharge passage, a plunger reciprocable within thecylinder toward and away from the head portion and including a slidevalve en gaging the bore of thecylinder, said slide valve havingcircumferentially extending leading and trailing cut off marginsarranged to cooperate with the inlet port so as to'close offsaid inletport during a portion of each stroke of the plunger and to dischargefuel through the discharge passage when the lunger is moving-in adirection from the fuel inlet toward the fuel discharge passage, andfuel passageway means extending between the cut ofi' margins of thevalye,said

passageway means being disposed in such angular relation as to cause thepressure of the fuel therein to exert a thrust upon the plunger in thedirection of the fuel inlet port.

2. In a fuel pump fora high speed interna'l combustion engine, thecombination of a pump cylinder having a head portion, fuel inlet andoutlet means provided in the pump cylinder and spaced from the headportion thereof, fuel discharge means located near the head portion ofthe cylinder,a plunger dis-.

posed in the cylinder and arranged to reciprocate in directions towardand away from the head portion thereof, said plunger having a diametralport-ionfclosely fitting the bore of the cylinder and a reduceddiametral end portion, a slide valve secured to and extend- 1 5d ingabout a substantial portion of the circumference of the reduceddiametral portion of the plunger, said slide valve havingcircumferentially extending leading and trailing cutoff marginscooperating with said fuel inlet and outlet means for establishingcommunication between the bore of the cylinder and said fuel inlet andoutlet means. during a portion of each stroke of the plunger, saidleading and trailing cut off marginscbeing inclined with respect to eachother and the trailing cut off margin being spaced from-the enlargeddiametral portion so as to form an intervening annular chamber arrangedto communicate, during each stroke of the plunger, with said fuel inletand outlet means, a passageway formed between the circumferentialendportions of the valve and extending be tween the end of the plungerand said annu lar chamber, and means for adjusting the relative angularpositions of the slide valve with respect to the fuel inlet and outletmeans.

2-3. In a fuel feeding system for a high speed internal combustionengine, the combination of a plurality of pump cylinders having a fuelinlet and a fuel outlet, a plunger rcciprocable within each pumpcylinder, cut off slide valve means provided on each plunger andcooperating with-their associated fuel inlet means during a portion ofeach working stroke of the plunger for effecting periodic discharge offuel under pressure through the outlet means, said slide valve havingleading and trailing cut off margins inclined with respect to. eachother so as to vary the quantity of fuel discharged through'the fuel outlet in accordance with its angular position in the cylinder, a memberassociated with each individual plunger for adjusting the angularposition of the same in the cylinder, said adjusting members beingdisposed in spaced, parallelrelationshi p, and common master adjustingmeanscooperating with each of said adjusting members for effectingsimultaneous and coextensive movements thereof, said master adjustingmeans extending in a direction andtrailing out off margins inclined withrespect to each other so as to vary thequantity of fuel dischargedthrough the fuel outlet in vaccordance with the angular position of thevalve in the cylinder, a member associated with each individual plungerfor adjusting the angular position of the same in the cylinder, saidadjusting members being disposed in spaced, parallel relationship, and arotatably mounted master member extending at right angles to the,respective individual adjusting members and engaging said individualadjusting members so as to effect simultaneous and co-extensivemovements thereof.

5. In a fuel feeding system for a highspeed internal combustion engine,the combination of a plurality of pump cylinders having fuel inlet and afuel outlet, a plunger reciprocable within each pump cylinder, cut offslide valve means provided on each plunger andcooperating with theirassociated fuel inlet means during a portion of each working thebeginning of the pressure stroke (if the plunger. With such a form ofinlet port, both ofits edges '64 and 65 are defined by helixes and theupper edge'64-i's adapted to cut oil the port '14 when it coincides withthe upper edge or margin of the valve 22.

' Referring now' particularly to Fig. 8, I

show the relative angular positions of-the valve and the port for arelatively heavy load tance a and words, fuel is fed into the engineduring the and a lon" period of fuel injection while'F ig. 9 shows therelative angular positions of the valve and the port for a relatvelylight load and short period of fuel injection. In both of theseviews, the inlet port 14 is s own 111 dot and dash lines asbeing infront'of the valve 22 in order to make the illustration as clear aspossible. With the valve 22' and its lunger 18 in the angular positionshown 1n ig. 8, it will be seen that the injection eriod is relativelylon due to'the fact thatt e disi is considerable. In other upward strokeofethe plunger 18 until such time as the edge or'm'argin 66 of the valvepasses the lower-edge of the inlet'port,

whereupon the fuel in the pump cylinder 17 u is relieved through theinlet port 14 to the conduit 16. It will be further'apparent from Fig. 8that the upper edge or margin 67 of the valve22 is disposed only arelatively short distance 6 above the upper-edge 64 of the inlet port sothat the time of injection is made, relatively late, the

period of injection not starting until such time as 67 of thevalve'has'passed edge 64 of the inlet port. H j Referring now to Fig.9," this figure shows the valve 22 and plunger 18 in a different tion-22 assumes a higher angular positign from that sh'own in Fig.8,

the settingofthevalve in relatively light load. F As fromthis firelativel tance a and b in Fig. 8 so that theperiod of fuel injection isofmuch shorter duration. It will also beap arent from Fig. 9 that, due

Fig. 9 being for will be apparent to the angular a justment of theplunger 18,

the leading edge or margin 67 of the valve ing between the upper edge ofthe inlet port 14 and the upper edge'or margin 67 "of the 'valve'22 isconsiderabl greater than the distance b in Fig.8 an consequently thetiming of the injection period is made relatively early. In other words,my valve 'ma be so formed that the timing is made later 2hr full loadsand earlier for light loads, but it will I be apparent that'thetimingmay' be the same or opposite if desired by the upper edge of theinlet 67 of the valve 22 simply arranging port and the edge to suita'nydesired condi- As shown in Figs. 8 and 9, the upper and lower edges ofthe inlet port preferably exwith the leading edge over the upper adirection as to 'fuel injection for full load and. a later period offuel injection for light load. In this emre, the distance c and d is sort" as compared with the dis-.

position in the cylinder and consequently the distance d interven 'bereadily adjusted by tend in the same general direction or coincide withthe leading and trailing edges or margins ofthe valve so that a sharperrapid beginning and endingof the in ection period .isassured andconsequently the fuel is very accurately metered. While I have shown aform of inlet port in which the upper and lower edges are made tocoincide with the cut-off edges of the valve, nevertheless it is to beunderstood that my invention is not restricted to such an arrangementinthat with some forms of engine, it may not be necessary todefine thefuel injection period so sharply,

and in such cases, the edges of the inlet rt need not coincide with thecut-ofi face 0 the valve. I

In Fig. 10,.I show a different form of'valve 71 wherein the leading orcut-oil margin-72 the axis of the 'cylin-,

is arranged normal to g der so that the time of injection is the 'sameirrespective of the length of the period of fuel 'injectign As' in. thevalve shown in Figs. 8 and 9', the trailing margin 73; is so arrangedthat the period of fuel injection -=trailing margin 76 arrangedashere'tofore.

the'lea'ding and trailing margins of the However, in this embodiment,the 'leadin 7 or cut-oil margin 77 is angularly dispose with respect tothe cylinder axis but in such provide an earlier period of bodiment, theinlet port isrepresented at 78.

From the foregoing, it will be apparent that I have devised an improvedfuel injection pump for internal combustion engines which is simple ofdesign, easy of manufacture and which is capable of operation with aminimum amountof same time assuring an quantity of fuel to the will befurther apparent a fuel injection system for internal combustion engineswhich is extremely flexible in leakage while at the accurately meteredengine cylinder. It

operation in that the'timing of the fuel injection period may beautomatically varied "111 response to the load or to the length ofperiod of fuel injection merely by angular adjustment of the plungerwithin the cylinder. Furthermore, allof the plungers may besimultaneously adjusted by manlpulation of the lever 37 while individualadjustment of each plunger may be had by manipulation of the respectiveracks. In addition, the phase relationship of the entire fuel injectionsystem relative to the engine cycle may manipulation of the lever 63. I

that I have invented I stroke of said plunger for effective periodicdischarge of fuel under pressure through the outlet means, said slidevalve having leading and trailing cut off margins inclined with respectto each other so as to vary the quantity of fuel discharged through thefuel outlet in accordance with the angular position of the valve in thecylinder, means for reciprocating each of the plunger-s and including across head member. longitudinally extending gear teeth disposed aboutthe periphery of each of said cross head members, a rack meshing withthe gear teeth of each cross head member, said individual racks beingdisposed in parallel relationship, and a master adjusting memberextending at right angles to the individual members and engaging thesame for effecting simultaneous and co-extensive adjustments thereof.

6. In a fuel feeding system for a high speed internal combustion engine,the combination of a plurality of pump cylinders having a fuel inlet anda fuel outlet, a plunger reciprocable within each pump cylinder, cut offslide valve means provided on each plunger and cooperating with theirassociated fuel inlet means during a portion of each working stroke ofthe plunger for effecting periodic discharge of fuel under pressurethrough the outlet means, said slide valve having leading and trailingcut off margins inclined with respect to each other so as to vary the,quantity of fuel discharged through the fuel outlet in accordance withthe angular position of the valve in the cylinder, means forreciprocating each of the plungers and including a cross head member,longitudinally extending teeth disposed about the periphery of each ofsaid cross head members, a separate rack for adjusting each cross headmember, said separate racks being disposed in side-byside relation andhaving teeth provided in one side thereof for engaging the teeth oftheir associated cross heads, a second group of teeth provided in eachof said racks, said second group of teeth being provided in a side ofthe rack which is at right angles to the side containing the teethengaging the cross head, and a rotatably mounted master adjusting memberprovided with toothed portions engag ng the second group of teeth of therespective separate racks for effecting simultaneous and co-extensiveadjustments of the latter.

7. In a fuel feeding system for a high speed internal combustion engine,the combination ofa plurality of pump cylinders having a fuel inlet anda fuel outlet, a plunger reciprocable within each pump cylinder, cut offslide valve means provided on each plunger and cooperating with theirassociated fuel inlet means during a portion of each working stroke ofthe plunger for effecting periodic discharge of fuel under pressurethrough the outlet means, said slide valve having leading and trailingcut off margins inclined with respect to each other so as to vary thequantity of fuel dischar ed through the fuel outlet in accordance witthe angular position of the valve in the cylinder, a member associatedwith each individual plunger for adjusting the angular position of thesame in the cylinder, said individual adjusting members being disposedin side-byside relation, means embodied in some of said individualadjusting members for eflecting an alteration in the angular position oftheir associated plungers and valves relative to the other plungers andvalves, and master adjusting means engaging each of said individualadjusting members for effecting simultaneous and co-extensive movementsof the latter, said master adjusting means extending in a directionwhich is substantially normal with respect to the direction of movementof said individual members.

8. In a fuel feeding system for a high speed internal combustion engine,the combination of a plurality of pump cyl nders having a fuel inlet anda fuel outlet, a plunger reciprocable within each pump cylinder, cut offslide valve means provided on each plunger and cooperating with theirassociated fuel inlets during a portion of each working stroke of theplunger for effecting periodic discharge of fuel under pressure throughthe outlet means, said slide valve having leading and trailing cut offmargins inclined with respect to each other so as to vary the quantityof fuel discharged through the fuel outlet in accordance with theangular position of the valve in the cylinder, means for reciprocatingeach of the plungers and including a cross head member,longitudinally-extending gear teeth disposed about the periphery of eachcross head member, a separate adjusting rack for each cross head member,said separate adjusting racks being disposed in side-by-side relationand each rack having a group of gear teeth provided in one side thereofand engaging the teeth of their associated cross head and a second groupof teeth provided in a side of the rack which is normal to the sidecontaining the first group, means embodied in some of the individualracks for adjusting the position of the second group of teeth relativeto the first group, whereby the angular position of the individual pumpplungers and valves may be adjusted relative to the remaining pumpplungers and valves, and a rotatably mounted master adjusting memberprovided with toothed portions engaging the second groups of teeth ofthe respective adjusting racks, said master adjusting member extendingat right angles to the individual adjusting racks.

In testimony whereof. I have hereunto subscribed my name this 3rd day ofJuly, 1928.

HERBERT T. HERB.

